The conventional method for recovering vanadium from vanadium-containing ores includes as an initial step the roasting of the vanadium ore with a sodium salt to form roasted products which contain sodium vanadate in solid form. The roasted material is then cooled, crushed, ground and water leached in agitation leach tank(s) in a conventional manner. The solubilized sodium vanadate in solution is recovered from the solids through conventional solid-liquid separation such as filtration or counter-current decantation. The tailings are transported to a tailings pond and the sodium vanadate solution is processed for the recovery of vanadium. The latter step generally involves precipitating the vanadium as ammonium metavanadate. In some instances, the filtrate is evaporated after precipitation to recover the sodium salt and to avoid liquid effluent disposal.
In vanadium recovery methods, both the percentage of the total vanadium values that are recovered and the grade of the leach liquor, that is, the concentration of vanadium in the leach liquor, are important to the economics of the methods. Clearly, recovery methods are sought which not only enable a high percentage of recovery of vanadium but also provide a high grade of leach liquor.